Product Description

C1q/Factor D-depleted serum is normal human serum in which complement proteins C1q and factor D have been depleted by ion exchange and immunoaffinity chromatography. The product is tested for C1q and factor D proteins by double immunodiffusion and the absence of C1q and factor D is measured by testing classical and alternative pathway function. The product is certified to exhibit less than 5% classical and alternative pathway activity. After reconstitution with purified C1q protein (70 µg/mL), C1q/Factor D-depleted serum is certified to possess a functional classical pathway for complement activation (Morgan, B.P. (2000); Dodds, A.W. and Sim, R.B. (1997)).Similarly, a functional alternative pathway can be reconstituted by addition of purified factor D (1.4 µg/mL) indicating that all other complement components necessary for alternative pathway activation are present. Lectin pathway activity is not tested, but it would be expected to be active.

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Complement Technology的C1是级联反应中的第一个补体成分，称为补体经典途径。C1与抗原结合的抗体（免疫复合物）结合并被其激活，从而产生引发级联反应的蛋白酶。C1实际上是钙依赖性复合物中结合在一起的三种不同蛋白质（C1q，C1r和C1s）的非共价复合物。C1q通过其六个臂中的两个或多个与IgG或IgM的Fc结构域结合。多臂与免疫复合物的结合被认为会引入压力，从而导致复合物中的两个C1r蛋白（蛋白酶酶原）自身激活，从而产生两种活性的C1r丝氨酸蛋白酶（Morikis，D.和Lambris，JD（2005））。 。这些激活的C1r亚基裂解并激活复合物中的两个C1s蛋白酶酶原。活化的C1裂解补体成分C4，释放出C4a，并启动C4b与活化表面的共价连接。活化的C1也切割C2，并且C2的较大片段结合至表面附着的C4b，形成C4b，C2a，其为经典途径的C3 / C5转化酶。